Abstract

The crystalline quality of silicon-on-insulator fabricated by a wafer bonding technique was examined by spectroscopicellipsometry and Raman spectroscopy. The detailed modeling of the experimental ellipsometric data yields information about structuraldefects in the silicon-on-insulator layer. The dielectric function of the silicon on insulator that best models the experimental ellipsometric data includes a physical mixture of crystalline silicon and about 4%–7% of amorphous silicon, suggesting a slight lack of long-range order of the silicon atoms in the silicon-on-insulator layer. The use of a dielectric function other than that of pure crystalline silicon is supported by Raman spectroscopic results that indicate the presence of structuraldefects in the silicon-on-insulator layer. These structuraldefects may be due to the effects of hydrogen implantation used in the fabrication process of silicon-on-insulator, and∕or the strain imposed by the lattice mismatch between the buried layer and the silicon substrate, and subsequently relaxed under high-temperature annealing.